/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.dolphinscheduler.rpc.remote;

import org.apache.dolphinscheduler.remote.config.NettyServerConfig;
import org.apache.dolphinscheduler.remote.utils.Constants;
import org.apache.dolphinscheduler.remote.utils.NettyUtils;
import org.apache.dolphinscheduler.rpc.codec.NettyDecoder;
import org.apache.dolphinscheduler.rpc.codec.NettyEncoder;
import org.apache.dolphinscheduler.rpc.common.RpcRequest;

import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.epoll.Epoll;
import io.netty.channel.epoll.EpollEventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.timeout.IdleStateHandler;

/**
 * NettyServer
 */
public class NettyServer {

  private static final Logger logger = LoggerFactory.getLogger(NettyServer.class);

  /**
   * boss group
   */
  private final EventLoopGroup bossGroup;

  /**
   * worker group
   */
  private final EventLoopGroup workGroup;

  /**
   * server config
   */
  private final NettyServerConfig serverConfig;

  /**
   * server bootstrap
   */
  private final ServerBootstrap serverBootstrap = new ServerBootstrap();

  /**
   * started flag
   */
  private final AtomicBoolean isStarted = new AtomicBoolean(false);

  /**
   * server init
   *
   * @param serverConfig server config
   */
  public NettyServer(final NettyServerConfig serverConfig) {
    this.serverConfig = serverConfig;
    if (Epoll.isAvailable()) {
      this.bossGroup = new EpollEventLoopGroup(1, new ThreadFactory() {
        private AtomicInteger threadIndex = new AtomicInteger(0);

        @Override
        public Thread newThread(Runnable r) {
          return new Thread(r, String.format("NettyServerBossThread_%d", this.threadIndex.incrementAndGet()));
        }
      });

      this.workGroup = new EpollEventLoopGroup(serverConfig.getWorkerThread(), new ThreadFactory() {
        private AtomicInteger threadIndex = new AtomicInteger(0);

        @Override
        public Thread newThread(Runnable r) {
          return new Thread(r, String.format("NettyServerWorkerThread_%d", this.threadIndex.incrementAndGet()));
        }
      });
    } else {
      this.bossGroup = new NioEventLoopGroup(1, new ThreadFactory() {
        private AtomicInteger threadIndex = new AtomicInteger(0);

        @Override
        public Thread newThread(Runnable r) {
          return new Thread(r, String.format("NettyServerBossThread_%d", this.threadIndex.incrementAndGet()));
        }
      });

      this.workGroup = new NioEventLoopGroup(serverConfig.getWorkerThread(), new ThreadFactory() {
        private AtomicInteger threadIndex = new AtomicInteger(0);

        @Override
        public Thread newThread(Runnable r) {
          return new Thread(r, String.format("NettyServerWorkerThread_%d", this.threadIndex.incrementAndGet()));
        }
      });
    }
    this.start();
  }

  /**
   * server start
   */
  public void start() {
    if (isStarted.compareAndSet(false, true)) {
      this.serverBootstrap
          .group(this.bossGroup, this.workGroup)
          .channel(NettyUtils.getServerSocketChannelClass())
          .option(ChannelOption.SO_REUSEADDR, true)
          .option(ChannelOption.SO_BACKLOG, serverConfig.getSoBacklog())
          .childOption(ChannelOption.SO_KEEPALIVE, serverConfig.isSoKeepalive())
          .childOption(ChannelOption.TCP_NODELAY, serverConfig.isTcpNoDelay())
          .childOption(ChannelOption.SO_SNDBUF, serverConfig.getSendBufferSize())
          .childOption(ChannelOption.SO_RCVBUF, serverConfig.getReceiveBufferSize())
          .handler(new LoggingHandler(LogLevel.DEBUG))
          .childHandler(new ChannelInitializer<SocketChannel>() {

            @Override
            protected void initChannel(SocketChannel ch) {
              initNettyChannel(ch);
            }
          });

      ChannelFuture future;
      try {
        future = serverBootstrap.bind(serverConfig.getListenPort()).sync();
      } catch (Exception e) {
        logger.error("NettyRemotingServer bind fail {}, exit", e.getMessage(), e);
        throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()));
      }
      if (future.isSuccess()) {
        logger.info("NettyRemotingServer bind success at port : {}", serverConfig.getListenPort());
      } else if (future.cause() != null) {
        throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()), future.cause());
      } else {
        throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()));
      }
    }
  }

  /**
   * init netty channel
   *
   * @param ch socket channel
   */
  private void initNettyChannel(SocketChannel ch) {
    ch.pipeline()
        .addLast(new NettyDecoder(RpcRequest.class))
        .addLast(new NettyEncoder())
        .addLast("server-idle-handle", new IdleStateHandler(0, 0, Constants.NETTY_SERVER_HEART_BEAT_TIME, TimeUnit.MILLISECONDS))
        .addLast("handler", new NettyServerHandler());
  }

  public void close() {
    if (isStarted.compareAndSet(true, false)) {
      try {
        if (bossGroup != null) {
          this.bossGroup.shutdownGracefully();
        }
        if (workGroup != null) {
          this.workGroup.shutdownGracefully();
        }

      } catch (Exception ex) {
        logger.error("netty server close exception", ex);
      }
      logger.info("netty server closed");
    }
  }

}
